Having your furnace and air conditioning unit serviced is important in air quality and saving money on your energy bills. You wouldn't believe the amount of gunk build-up in your blower/drum and the ducts as well. Also, keep big items away from the intake ducts inside your home. This can lead to extra effort put on your system do to poor air circulation which means higher bills. If you don't know whcih vents are which, most service heat/ac furnace companies will give free estimates...just make sure you are there to observe what they are telling you.

Another thought about IAQ is whether to have double-paned, super tightly sealed windows in one's home (or workplace, if you've any say about this). When a building "breathes" (has a natural exchange between indoor and outdoor air), the indoor air is less toxic. Modern, efficient windows can cause indoor air pollution.